Improvement in tanning compounds



' leather.

into leather is short, being only ten days in UNIT D STATES PATENT, OFFICE.

' CHARLES J. TINNERHOLM, OF BROOKLYN, ASSIGNOR, BY Mnsnn ASSIGN- MENTS, TO THE HAMMONASSETT SOLE LEATHER COMPANY, OF NEW YORK, N. Y.

IMPROVEMENT IN TANNING COMPOUNDS.

Specification forming part of Letters Patent No. 200,108, dated February 5, 1878; application filed August 1, 1877.

To all whom it may concern:

Be it known that I, CHARLES J. TINN'ER- HOLM, of the city of Brooklyn, in the county of Kings and State of New York, have in vented a new and useful Improvement in Tanning and Improving Leather, of which the following is a full, clear, and accurate description:

The nature and object of my invention is a new method or process of tanning and improving leather, which shall be speedy in its action, simple in operation, and inexpensive as to its cost.

The present process of tanning leather is long and tedious. The hides, after they have been deprived of their hair, are placed in tanks or vats filled with water and tan-bark, and allowed to remain there several days. The hides are then removed, and the tank or vat replenished with water and tan-bark. They are then placed again in the vat, and this operation is repeated many times, the whole process taking from three to four months. In subjecting the hides to this treatment, the water of the vats is kept at the high temperature of 100 Fahrenheit, and this temperature is kept uniform, as otherwise the leather will be spoiled. It is therefore necessary to employ a force of skilled workmen, and to have the vats watched with great care, which involves a large expense.

My invention does away with all these difficulties experienced in tanning leather by the present mode.

The hides are placed in my solution and are not removed until they are converted into The time taken to convert the hides the case of sole-leather, and about two days in the case of leather other than sole-leather. No care is necessary to keep the solution at a high and uniform temperature. The materials of which my solution is made are not expensive and can readily be procured.

It will thus be seen that my invention is simple, labor-saving, and cheap. The leather produced by it also possesses qualities which 'leathermade by the old process does not possess. All grease and all other matter harmful to the leather are entirely expelled, which is only partially the case in the leather manufactured by the present method now commonly in use.

The leather made by my new process is far more solid and durable. It can be readily known in the market by its color, which is light brown on the outside and somewhat darker brown on the inside.

The ingredients used in compounding my solution and the manner of making it are hereby given.

- I prefer tanning fifty hides together, or, as is usual, the hides being cut in two, one hundred pieces in one vat. I prefer tanning this number together, as this is the usual number which, by the old process, are subjected to treatment at the same time in one vat, and the vats are adapted for tanning that number. The proportions in which the various ingredients are mixed I will therefore give with reference to tanning fifty hides or one hundred pieces. For tanning that number I use the following solution: I add one hundred and fifty pounds of Peruvian bark (cortex Ohinae rubrae) to two hundred and twenty-five gallons of boiling water, and boil for one hour. On cooling, the mixture should be of 35 of strength, measured on the barkometer or bark cylinder, Fahrenheit scale. If not, let it boil a little longer, until that degree of strength is obtained. I also boil for fifteen minutes one hundred and fifty pounds of catechu (gummi catechu) in two hundred and twenty-five gallons of boiling water. On coolin g, the mixture should contain 35 of strength, measured on the barkometer or bark-cylinder, Fahrenheit scale. If not, let the mixture boil a little longer, until it obtains that degree of strength. I also dissolve thirty-seven and a half pounds of salt of tartar, (kali carbonicum purum,) together with thirtyseven and onehalf pounds of oxide of zinc, (zincum oxidat album,) in seventy-five gallons of cold water. This mixture should contain 10 of strength, measured on the barkometer or bark-cylinder, Fahrenheit scale. I also dissolve seventy-five i I takeall theseliquids,preparedintheman- 7 her above described, and place themtogether 1 ina tank 0r Vat, in which I: also place the hides for tanning, from which the hair has been V pounds of alum; (alumeny-(Al K' fl $0,, 24

;H O)in seventy-five gallons of; cold; water.

V This mixtureshould contain 15 of strength: 1: I measured on the barkometer or bark-cylinder,

: Fahrenheit scale. 7 I r r ,Of course, a greater or less number of hides- V maybetannedatthe same time, as desired,

andthen the: relative proportionsof the i I gredients of the mixtures above described must 7 be varied accordingly, theisaine relative proportions: of the said ingredients :to the water 1 in which they are dissolved being preserved.

previously removed, I let these hides in:

V the solution for ten days, in case I wish to-tan I V sole-leather, and for two days in case i of; all other leather but sole-leather, After they -ha've remainedin the solution the requisite V 7 time, I take them out and hang them "1111130:

dry in buildingsor places where the air can getto them readily, but wherethey'shall not be exposed to the direct rays oiithesun, I i I The hides will try in about three days, and

are then fully converted intorleathenvfrom f V which all greaseand all other matteriharmful V to leather has been entirely expelled, and are ready for use.

My invention is also useful in treating leather which has been tanned by the old process= 'By placing; such: leatherin my solution andallowing it to remain there for one day, any grease which may remain in: the leather is removed, andthe leather is made 10f superior'quality, gaining in weight and solidity, T

as my process removes all air from the pores of the. leather and fills theni up solid; Y Y I I After onebatch: of hides orleather has been l I r treated in the solution it will become depleted in strength; but it is not necessary to use an entirely new solution for tanning the next v 1 :batchof' hides, butrby adding one-fourth in i V quantity of new solution to the old solution it i I i i will regain the requisite strength, and thus I the original solution, with the addition'of one V fourth in quantity of new solution, as each i V batch of hides'is tanned, can? be used a considerable length of time before it isnecessary' V r V to entirely renew it. l

claim, and desire to secureby Letters Patent,

ris 7 r'The; process of tanning and improving 7 leather by treating the hides or leather for T the respective times specified in a solution'of Peruvian 'bQ/IkfGH/tQGhII, Glaubers salt, salt of tartar, oxide of zinc,and alum, compouml- 1 ed in the proportions :and of the strength specified, substantially as described.

.' In testimony whereoflj have hereunto set i Z vmy hand this 30thday of July, 1877'.

CHARLES J; TINNERHOLM. In presence of Y I LOUIS W. FROST, o CHARLES G. 0012.

Having time described 'myinv'ention, what I r r 

